A wind turbine includes a tower and a generator on the tower. The modulation signal generating circuit includes a sine wave signal generating circuit that generates a sine wave signal and a pulse signal generating circuit that generates a modulation signal by converting the generated sine wave signal to a pulse signal using a step recovery diode. In addition to an automated portion, the present invention allows a human dialog designer to model the way the system elicits information, giving a human feel to the dialog and a better customer experience. At least one spacing element having the same annular configuration as the cages can be provided to effect the stacked attachment of one cage with another in rigid axial alignment. The slider ground pad is disposed in electrical communication with the main and return poles for electrically grounding the main and return poles. 25 at quarter-track locations, and with substantially linear slope therebetween.